Device and method for treatment of spinal deformity

ABSTRACT

The present invention generally relates to methods and device for treatment of spinal deformity, wherein at least one tether is utilized to maintain the distance between the spine and the an ilium to (1) prevent increase in abnormal spinal curvature, (2) slow progression of abnormal curvature, or (3) impose at least one corrective displacement and/or rotation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is non-provisional application which claimspriority to U.S. Provisional Application Ser. No. 61/744,525 filed onSep. 28, 2012, which is incorporated in its entirety herein.

FIELD OF THE INVENTION

The present invention generally relates to methods and devices fortreatment of spinal deformity.

BACKGROUND OF THE INVENTION

Scoliosis is a spinal deformity characterized by an abnormal curvatureof the spine in the coronal plane. Adolescent idiopathic scoliosis (AIS)is the most prevalent type of scoliosis which develops duringadolescence in an otherwise healthy patient and typically ceases at theonset of skeletal maturity. The cause of the disease is presentlyunknown.

Current surgical treatment of scoliosis involves manipulation of thespinal column and attachment of corrective devices for fusion of aportion of the spine. One such system, the Cotel-Dubousset systemutilizes rigid metal rods attached to the spine. The rods aremanipulated during surgery in an attempt to reduce abnormal curvaturesand rotations of the spinal column. Large loads are exerted on the spinefor correction which risks the patient's neurological condition.Recovery from these procedures can be lengthy and painful. Also, ifnormal lordosis and kyphosis are not restored, a condition called “flatback syndrome” may occur causing chronic pain. Even a successfulprocedure rarely results in a normal spinal curvature and the patient isleft with an immobile spinal section. The discs above and below thefusion zone are at risk of future degeneration due to the increasedmechanical demands placed on them.

It is therefore evident that there are flaws in prior art methods anddevices. Most prior art devices are part of the load path of the spinalcolumn. For example, it is understood that the Cotel-Dubgousset systemrigidly attaches stiff metal rods to the spine. A structure having tworoughly parallel support members relies primarily on the stiffer of thetwo members for transmission of loads. Therefore, loads exerted on aninstrumented spine are transferred through the implant instead ofthrough the spine. Spinal loads can be significantly large, and theimplants will not support such loads indefinitely. Fatigue failure ofthe implant will occur if fusion is delayed.

Therefore, there is an unaddressed need that exists to provide a new andbetter system for correcting spinal deformities.

SUMMARY OF THE INVENTION

The current invention describes methods and devices for treating spinaldeformity which offer significant improvements over prior art methodsand devices. In general terms the present invention is used to securethe distance between an ilium and the spine to either correct ormaintain spinal curvature. There are many embodiments of the inventionwhich will achieve the stated objectives, some of which will bepresented in the following summary.

In one embodiment of the invention, at least one device is attachedbetween the spine and the pelvis which incorporates at least oneflexible tether. Attachment of the flexible tether to the spine andilium involves implantation of anchoring means and then attachment ofthe tether to the anchoring means. For example, at least one bone screw,pedicle screw, cannulated bone screw, clamp, plate, bone anchor, orshackle might be anchored to at least one vertebra and another to aportion of the ilium and the flexible tether may be attached to both.Other means of attachment will be clear to one practiced in the art.Alternatively, a loop of material may be placed around a bony structure(e.g. spinous process, transverse process, lamina or pars) or a holethrough a bony structure through which the flexible tether is passed.

It should be noted that the present invention enables manipulating thevertebral column to correct the deformity by securing the tether to aportion of the ilium and a portion of the vertebral column; the abilityto correct deformity by correcting the effective length of the tetherbetween the ilium and vertebra over time; and correcting deformity bythe natural growth of the spine by allowing the tether to maintaineffective length between the vertebral column and the ilium.

Adjustment of the distance between the spine and ilium is achieved byvarying the location at which the tether is attached to the anchoringmeans. The tether does not change lengths during the adjustment process,but the distance between the attachment points does, much like adjustinga belt around your waist. Taking advantage of the inherentviscoelasticity of spinal structures, the curvature may be graduallycorrected by small incremental corrections over a protracted period oftime, whereby the original incision is re-opened, or a new incision nextto the original incision is created and the attachment means isdisengage and then reengaged at a different location along the tether.Alternatively the patient's growth may be used to achieve correction.

Alternatively, the tether may branch into multiple tethers to providemultiple attachments to the spine and/or ilium. If more than one tetheris used, each can be attached to a different vertebra, or multipletethers can be attached to the same vertebra. Tethers can be attached toeither or both sides of the vertebral column and either opposing sidesof ilium as needed to generate correction of the spinal deformity. Acrossing pattern whereby a tether is attached to the right side of thevertebra (e.g. the right pedicle) and left ilia, or vice versa, ispossible. Also, a tether may be attached to a vertebra and then passedthrough an eye screw or other guiding device which is attached to theilium (or both ilia) and then attached to a second vertebra with apedicle screw or other means. In can be envisioned by one skilled in theart that guiding devices may be utilized on a number of vertebrae or onethe ilium or ilia. The tether may also originate with an attachment tothe pelvis, pass through any number of guide members attached to thespine, and then terminate at the pelvis again.

These and other aspects of the present invention, will become apparentfrom the following description of the embodiments taken in conjunctionwith the following drawings, although variations and modificationstherein may be affected without departing from the spirit and scope ofthe novel concepts of the disclosure.

The present invention provides an improved method of arresting a spinaldeformity whereby at least one device is surgically attached between thespine and the ilium. Also, the present invention provides a system and amethod for correcting a spinal deformity whereby at least one device issurgically attached between the spine and the ilium.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an illustration of a posterior view of a deformed human spinewith an implanted device according to one embodiment of the presentinvention;

FIG. 2 is an illustration of a posterior view of a corrected human spinewith the implanted device shown in FIG. 1;

FIG. 3 shows a spinal anchoring means in the form of two pedicle screwsand a rod onto which is secure an attachment mechanism and the tether;

FIG. 4 illustrates an attachment mechanism and the method of attachingit to the spinal anchoring mechanism;

FIG. 5 shows the anchoring mechanism of the ilium (not shown) and themethod of attaching the tether to it;

FIG. 6 shows a long pair of forceps to be used for passing the tetherbeneath the skin;

FIG. 7 illustrates the use of the forceps of FIG. 6 in passing thetether beneath the skin;

FIG. 8 illustrates an alternative embodiment of the tether clamp andelongate rod according to the present invention;

FIG. 9 illustrates another embodiment of a clamp or anchor according tothe present invention;

FIG. 10 shows a cross-sectional view of the device shown in FIG. 9;

FIG. 11 shows another embodiment of a clamp or anchor according to thepresent invention;

FIGS. 12 and 13 shows a closed head clamp according to the presentinvention;

FIGS. 14 and 15 shows yet another embodiment of a closed head clampaccording to the present invention; and

FIGS. 16-18 illustrate various methods of coupling the tether toportions of the spine and/or ilium.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses. The invention being thus described, it will beobvious that the same may be varied in many ways. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention, and all such modifications as would be obvious to one skilledin the art are intended to be included within the scope of the followingclaims.

FIG. 1 is an illustration of a posterior view of a deformed spine 104whereby the preferred embodiment of the device 200 is attached to anilium 102 and a vertebra 100. Device 200 includes a tether 204 having afree end 206 and that is configured to be attached to the ilium and aportion of the vertebra. Specifically, in one embodiment, two attachmentmechanisms such as pedicle screws 300 are anchored to the vertebra ofthe spine by insertion into opposing pedicles, and a transverse rod 311is attached to the pedicle screws 300. It should be noted that althoughpedicle screws are provided in this particular embodiment, any othertype of anchoring mechanism such as hooks may also be used. A tetherclamp 310 is attached to rod 311 and the tether 204 is passed thoughtether clamp 310 and then passed down to the ilium 102 thereby securinga connection between the attached vertebra and the ilium. To attach thetether 204 to the ilium 102, an ilium anchor 210 is provided. The iliumanchor 210 includes a bore 211 and is configured to be attached to theilium by inserting the anchor 210 (threading) into a hole which has beendrilled or punched through the ilium 102. It should be noted that anyother similar mechanism to attach anchor 210 to the ilium 102 may alsobe utilized. Tether 204 is passed through hole or bore 211 in the iliumanchor 210 and then brought back to the vertebra 100 and passed againthrough the tether clamp 310. In other embodiments, the tether 204 mayonly be passed once through the tether clamp and ilium anchor 210.

FIG. 2 illustrates the correction of the spine of FIG. 1 using device200. As illustrated in FIG. 2, the free end 206 of tether 204 is pulledand the spine is manually manipulated during the surgery to achieve acorrection of the deformity. When a satisfactory curve magnitude isachieved, tether 204 is tightened within the tether clamp, effectivelylocking the distance between vertebra 100 and the ilium 102.

It should be noted that various levels of manipulation of the vertebralcolumn can be coordinated using the device. For instance, differentcurvatures of the spine can be achieved by changing the position of theanchor and the clamp on the tether with respect to the vertebral columnand the ilium. The locations along the tether where the clamp and anchorare attached determine an effective length of the tether, which in turnmaximizes the distance that the attached vertebra may move relative tothe position where the tether is attached at in the ilium. The scolioticcurve is corrected (or maintained) by adjusting the clamping andanchoring locations along the tether.

FIG. 3 shows a detailed view of pedicle screws 300, transverse rod 311,tether clamp 310 and tether 204. In a preferred embodiment tether clamp310 includes locking screw 312 which clamps tether clamp 310 onto rod311 as well as locking the tether 204 within the clamp 310.

FIG. 4 shows a detailed view of the tether clamp 310 coupled to thetransverse rod. The tether clamp 310 is configured with a slot 501 whichis provided through the tether clamp 310 and tether 204 is passedthrough slot 501. It should be noted that the tether may be passedthrough the slot multiple times, if necessary. Locking screw 312 is usedto secure the transverse rod 311 onto the tether clamp 310 and applies acompressive force upon the rod 311 onto the tether 204, thereby clampingthe tether 204 securely in place. It should be noted that although athreaded set screw is utilized in the present embodiment, any type oflocking element know in the art for securing the tether within tetherclamp may be used.

FIG. 5 shows a detailed view of an ilium anchor 210. Ilium anchor 210includes threads 212 for engagement with ilium 102 (not shown). Tether204 is passed through bore 211 and then passed back to the vertebralcolumn. A collar 215 is shown which keeps tether 204 adjacent to itself.

FIG. 6 shows an extra-long pair of forceps 900. FIG. 7 shows thepreferred method of passing the tether through an incision 845 andunderneath skin and other soft tissues. The forceps 900 are used to passthe tether though the openings in the tether clamp and used to tensionthe tether to correct the deformity of the curvature in the spine.

FIG. 8 illustrates another embodiment of a tether clamp 320 according tothe present invention. In this embodiment, the tether clamp 320 isconfigured with a through hole 322 that is configured to correspond to athrough hole 324 in an elongate rod 326 that is fixated to a portion ofthe spinal column. A fastening element 328 such as a set screw isprovided to couple the tether clamp 320 and the elongate rod 326together. The tether clamp 320 also includes openings 330, 332 which aredimensioned to receive and securely couple a tether 334 to the clamp320. The tether 334 is pulled through each of the openings 330, 332 tosecurely attach the tether 334 to the clamp 320 and the elongate rod326.

FIGS. 9 and 10 illustrate an alternative embodiment of a clamp and/oranchor 250 that can be used to secure a tether 252 to either thevertebral column or a portion of the ilium. More specifically, theanchor 250 of FIGS. 9 and 10 may be configured and dimensioned to beattached to a portion of the vertebral column or may be configured besecure the tether to the ilium. The anchor 250 is configured as a plate251 having at least two openings 254, 256 to receive fasteners 258, 260capable of fixating the plate to bone. The plate 251 includes a middleportion 262 having an opening 264 that is capable of receiving thetether 252. The middle portion 262 of the plate 251 is further providedwith a fastening element 266 to secure the tether 252 to the plate 251.As more clearly illustrated in FIG. 10, the fastening element 266 may bea set screw which directly contacts the tether 252 when tightened tosecure the tether 252 to the plate 251. It should be noted that anyother type of fastening element which is capable of securing the tetherto the anchor may be used, such as a pin.

FIG. 11 illustrates yet another embodiment of a clamp or anchor 400according the present invention. In this embodiment, the clamp and/oranchor 400 includes a first plate 402 and second plate 404 that aresecured to one another via a fastening element 406. The first and secondplates 402, 404 are may also include spikes 408 or similar type offeatures that bite into bone. Either the first or second plate 402, 404or both also includes an opening 410 for receiving a tether. The firstand second plates 402, 404 are positioned so that bone is in between,such as the ilium or a portion of the vertebral column. As the first andsecond plates 402, 404 are compressed into bone, the tether which ispositioned through the opening 410 and in between the first and secondplates 402, 404, is also securely locked between the plates and the bonethereby securing the tether to the plates 402, 404. In an alternativeembodiment, the tether is passed through the opening and secured to theanchor 400 by a clamp device such a belt clamp or secured by knottingthe tether around the edge of the anchor 400. It should be noted thatany type of mechanical mechanism to attach the tether to the anchor maybe used.

FIGS. 12-15 illustrate yet another embodiment of a clamp according tothe present invention. The closed head clamp 420 as illustrated in FIGS.12 and 13, includes a first opening 422 extending through the clamp 420in a first direction and a second opening 424 extending in a seconddirection. The first and second direction are generally perpendicular toone another. The first opening 422 is configured to receive an elongaterod 426 and the second opening 424 is configured to receive a tether428. The clamp 420 is further provided with a fastening element 430 thatis used to secure both the rod 426 and the tether 428. In thisembodiment, FIGS. 12 and 13 also illustrates that the second opening 424is positioned at a bottom portion of the clamp 420, thus, as thefastening element 430 is tightened, the fastening element 430 contactsthe rod 426 which is pushed against the tether 428 thereby securing thetether 428 and rod 426 within the clamp.

In an alternative embodiment of the closed head clamp as illustrated inFIGS. 14 and 15, the closed head clamp 432 includes a first opening 434and a second opening 436. The first opening 434 and the second opening436 are configured to be generally transverse to one another. The firstopening 434 is dimensioned to receive an elongate rod 438 and the secondopening 436 is dimensioned to receive a tether 440. The clamp 432 alsoincludes a fastening element 442, such as a set screw, which whentightened secures and locks the tether 440 and the elongate rod 438within the clamp 432. In this particular embodiment, the second opening436 is positioned between the fastening element 442 and the elongate rod438. When the fastening element 442 is tightened, the fastening element442 directly contacts the tether 440 which contacts the elongate rod 438thereby securely locking the tether 440 and the elongate rod 438 withinthe closed head clamp 432.

FIGS. 16-18 illustrate alternative embodiments of the inventive device.Specifically, FIG. 16 illustrates the use of clamp to attach the tetherto the lamina of a vertebra. As illustrated, the tether may encircle thelamina and may be tightened using a belt clamp. The other end of thetether is as shown in the earlier embodiments coupled to a portion ofthe ilium. Using this mechanism, the deformity of the spine may becorrected by manipulating the tether as well as the positioning of theclamp, as needed.

FIG. 17 shows a tether that includes a loop which is used to forcoupling the tether to the transverse rod to fixate the tether to thetransverse rod. FIG. 18 illustrates the coupling of the tether directlyto the ilium using another type of tether clamp. It should be noted thatin the examples provided of both anchor and clamps, these mechanicaldevices may be interchangeable.

It should also be noted that the tether of the present invention may becomposed of fabric, polymer, such as PET, or any other biocompatiblematerials. The tether can be a cable and can be dimensioned to be a wideelastic band which advantageously reduce the risk of damage to tissuelacerations or injury. In some embodiments, the tether can be is between2 and 900 mm. Also, to ensure that proper correction of deformities, atensioner can be included as part of the system to make sure that thetether are in proper tension and tightness.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the scope or spirit of the invention. Moreover,the improved bone screw assemblies and related methods of use need notfeature all of the objects, advantages, features and aspects discussedabove. Thus, for example, those skilled in the art will recognize thatthe invention can be embodied or carried out in a manner that achievesor optimizes one advantage or a group of advantages as taught hereinwithout necessarily achieving other objects or advantages as may betaught or suggested herein. In addition, while a number of variations ofthe invention have been shown and described in detail, othermodifications and methods of use, which are within the scope of thisinvention, will be readily apparent to those of skill in the art basedupon this disclosure. It is contemplated that various combinations orsubcombinations of these specific features and aspects of embodimentsmay be made and still fall within the scope of the invention.Accordingly, it should be understood that various features and aspectsof the disclosed embodiments can be combined with or substituted for oneanother in order to form varying modes of the discussed bone screwassemblies. Thus, it is intended that the present invention cover themodifications and variations of this invention provided that they comewithin the scope of the appended claims or their equivalents.

What is claimed is:
 1. A spinal system comprising: a clamp for receivingan elongate rod therein, wherein the clamp comprises a first opening forreceiving the elongate rod, and a second opening transverse to the firstopening for receiving a first portion of a tether, wherein the firstopening that receives the elongate rod is formed on an upper surface ofthe clamp such that the elongate rod is downwardly delivered therein; afastener downwardly received in the first opening formed on the uppersurface of the clamp, wherein the elongate rod is positioned between thetether and the fastener such that the fastener is not in direct contactwith the tether; an anchor configured to be implanted in the ilium, theanchor having a bore hole receiving a second portion of the tether,wherein when the anchor is implanted in the ilium, the tether extendsfrom one side of the ilium to the other side of the ilium, wherein whenthe fastener is actuated into the first opening, the elongate rodpositioned in the first opening and the tether positioned in the secondopening, the elongate rod contacts and compresses the tether, therebysecurely locking the elongate rod and tether within the clamp.
 2. Thesystem of claim 1, wherein the clamp is positioned on the elongate rodbetween two bone fasteners.
 3. The system of claim 1, wherein the clampcan be moved laterally on the elongate rod prior to tightening of thefastener.
 4. The system of claim 1, wherein the fastener is a set screw.5. The system of claim 1, wherein when the fastener is tightened thefastener applies a force against the elongate rod which applies a forceagainst the tether to securely lock both the tether and the elongate rodwithin the clamp.
 6. The system of claim 1, wherein the anchor includesthreads for engagement to the ilium.
 7. The system of claim 1, whereinthe second portion of the tether is passed through the bore hole of theanchor and coupled to a collar.
 8. The spinal system of claim 1, whereinthe positioning of the clamp or anchor is configured to modify thecurvature of the spine.
 9. A spinal system comprising: a clamp forcoupling to an elongate rod, wherein the clamp comprises a first openingfor receiving the elongate rod and a second opening for receiving atether, wherein the first opening that receives the elongate rod isformed on an upper surface of the clamp such that the elongate rod isdownwardly delivered therein; a fastener downwardly received in thefirst opening formed on the upper surface of the clamp for securing thetether to the elongate rod, wherein the elongate rod is positionedbetween the tether and the fastener such that the fastener is not indirect contact with the tether; an anchor configured to be implanted inthe ilium, the anchor having a bore hole receiving a second portion ofthe tether, wherein when the anchor is implanted in the ilium, thetether extends from one side of the ilium to the other side of theilium, wherein when the fastener is actuated into the first opening, theelongate rod contacts and compresses the tether, thereby securelylocking the elongate rod and tether within the clamp, and the tether issecurely positioned between a portion of a vertebral column and theilium.
 10. The spinal system of claim 9, wherein the fastener is a setscrew.
 11. The spinal system of claim 9, wherein the tether is loopedthrough the second opening of the clamp.
 12. The spinal system of claim9, wherein the elongate rod is extendable from laterally across thespinal column.
 13. A spinal system comprising: a clamp for coupling toan elongate rod and wherein the clamp comprises a first opening forreceiving a fastener and a second opening for receiving a tether,wherein the first opening that receives the elongate rod is formed on anupper surface of the clamp such that the elongate rod is downwardlydelivered therein; a fastener downwardly received in the first openingformed on the upper surface of the clamp for securing the tether to theelongate rod, wherein the elongate rod is positioned between the tetherand the fastener such that the fastener is not in direct contact withthe tether; an anchor configured to be implanted in the ilium, theanchor having a bore hole receiving a second portion of the tether,wherein when the anchor is implanted in the ilium, the tether extendsfrom one side of the ilium to the other side of the ilium, wherein whenthe fastener is actuated into the first opening, the elongate rodcontacts and compresses the tether, thereby securely locking theelongate rod and tether within the clamp, and the tether is securelypositioned between a portion vertebral column and the ilium, wherein theanchor is configured to secure the second portion of the tether.